Monitoring circuit for preventing star-delta step-down starting from being changed into full-voltage starting

Abstract

The utility model discloses a monitoring circuit for preventing star-delta step-down starting from being changed into full-voltage starting. The monitoring circuit comprises a first control circuit, a second control circuit, a third control circuit, a fourth control circuit, a fifth control circuit, a sixth control circuit and a seventh control circuit, the device has the advantages that by utilizing the linkage between a plurality of auxiliary contacts on a power supply contactor KM1, a star contactor KM3 and a plurality of layers of contacts of a stop button SB1, a star start button SB2 and an angle start button SB3 and under the matching of the monitoring effects of a first indicator lamp, a second indicator lamp, a third indicator lamp and a fourth indicator lamp, the device is lighted up in a strict sequence; when one lamp is not turned on, an operator can discover problems in time, does not carry out the next operation, is strict in logic and does not jump, so that the problem of motor burnout caused by adhesion of contacts of a contactor at present is solved, the problems are discovered and solved in time, economic loss is reduced, and smooth production is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of motor control, in particular to a monitoring circuit for preventing star-delta reduced-voltage starting from becoming full-voltage starting. Background Art

[0002] The starting moment of a three-phase asynchronous motor usually takes several seconds, usually 1 to 3 seconds. The instantaneous current is 4 to 7 times the steady-state value during operation. If the motor power is relatively large, the starting current will seriously affect the normal operation of the surrounding loads. Therefore, star-delta step-down starting is required to reduce its starting current.

[0003] Electrical equipment that adopts star-delta step-down starting has frequent use of contactors, which leads to adhesion of the auxiliary contacts of the contactors. Inexplicable motor burning accidents often occur. This is mainly due to the inability to start, stop, start and stop the star type, resulting in the motor not going through the step-down stage and directly starting at full voltage. The cause of this problem is poor contact linkage or poor contact of the contactor or push button switch. At the same time, the lack of a step-down stage is generally not easy to be discovered. Once the motor burns out, production will be delayed. At present, there is an urgent need for a monitoring circuit to prevent star-delta step-down starting from becoming full-voltage starting. Utility Model Content

[0004] The utility model aims to provide a monitoring circuit to prevent star-delta reduced-voltage starting from becoming full-voltage starting.

[0005] The utility model is implemented by the following technical scheme: a monitoring circuit for preventing star-delta reduced-voltage starting from becoming full-voltage starting, which includes a first control circuit, a second control circuit, a third control circuit, a fourth control circuit, a fifth control circuit, a sixth control circuit, and a seventh control circuit;

[0006] The first control circuit includes a switch of a circuit breaker QF, a normally closed contact of a thermal relay FR, a normally closed contact of a stop button SB1, a normally open contact of a star-shaped start button SB2, and a coil of a power contactor KM1, which are sequentially arranged in series, and the normally open contact of the star-shaped start button SB2 is connected in parallel with the normally open contact of the power contactor KM1;

[0007] The coil of the power contactor KM1 of the first control circuit is connected in parallel with the second control circuit;

[0008] The second control circuit includes a normally closed contact of an angle contactor KM2, a normally closed contact of an angle start button SB3, and a coil of a star contactor KM3 which are sequentially arranged in series;

[0009] The second control circuit is connected in parallel with a third control circuit;

[0010] The third control circuit includes a normally open contact of an angular contactor KM2, a normally closed contact of a star contactor KM3, and a coil of the angular contactor KM2, which are sequentially arranged in series, and the normally open contact of the angular contactor KM2 is connected in parallel with the normally open contact of the angular start button SB3;

[0011] The fourth control circuit is connected in parallel between the normally closed contact of the thermal relay FR of the first control circuit, the normally closed contact of the stop button SB1, the normally open contact of the star start button SB2, and the coil of the power contactor KM1;

[0012] The fourth control circuit includes a normally closed contact of a power contactor KM1, a normally closed contact of a stop button SB1, and a first indicator light HL1 which are sequentially connected in series;

[0013] The fifth control circuit is connected in parallel between the normally closed contact of the stop button SB1 of the fourth control circuit and the first indicator light HL1;

[0014] The fifth control circuit includes a normally closed contact of a star contactor KM3, a normally closed contact of an angle start button SB3, and a second indicator light HL2 which are sequentially connected in series;

[0015] The sixth control circuit is connected in parallel between the normally closed contact of the angle start button SB3 of the fifth control circuit and the second indicator light HL2;

[0016] The sixth control circuit includes a normally closed contact of an angular contactor KM2 and a third indicator light HL3 which are arranged in series;

[0017] The fourth control circuit is connected in parallel with the seventh control circuit;

[0018] The seventh control circuit includes a normally open contact of a power contactor KM1, a normally open contact of a star contactor KM3, a normally closed contact of a corner contactor KM2, and a fourth indicator light HL4 which are sequentially connected in series.

[0019] The utility model has the advantages of utilizing the linkage between the power contactor KM1, the star contactor KM3, the multiple auxiliary contacts on the star contactor KM3 and the multi-layer contacts of the stop button SB1, the star start button SB2 and the angle start button SB3, and under the cooperation of the monitoring function of the first indicator light, the second indicator light, the third indicator light and the fourth indicator light, they light up in a strict sequence. When one light is not on, the operator can find the problem in time and will not proceed to the next step of operation. The logic is strict and will not jump, which solves the current problem of motor burning caused by contactor contact adhesion, finds and solves the problem in time, reduces economic losses and ensures smooth production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the main power supply circuit of the motor in the utility model;

[0022] Figure 2 It is a schematic diagram of the monitoring circuit of the utility model;

[0023] In the figure: power contactor KM1, star contactor KM3, angle contactor KM2, stop button SB1, star start button SB2, angle start button SB3, circuit breaker QF, thermal relay FR, first indicator light HL1, second indicator light HL2, third indicator light HL3, fourth indicator light HL4, first control circuit 1, second control circuit 2, third control circuit 3, fourth control circuit 4, fifth control circuit 5, sixth control circuit 6, seventh control circuit 7. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] like Figure 1-2 As shown, a monitoring circuit for preventing star-delta reduced-voltage starting from becoming full-voltage starting comprises a first control circuit 1, a second control circuit 2, a third control circuit 3, a fourth control circuit 4, a fifth control circuit 5, a sixth control circuit 6, and a seventh control circuit 7;

[0026] The first control circuit 1 includes a switch of a circuit breaker QF, a normally closed contact of a thermal relay FR, a normally closed contact of a stop button SB1, a normally open contact of a star-shaped start button SB2, and a coil of a power contactor KM1, which are sequentially connected in series. The normally open contact of the star-shaped start button SB2 is connected in parallel with the normally open contact of the power contactor KM1.

[0027] The coil of the power contactor KM1 of the first control circuit 1 is connected in parallel with the second control circuit 2;

[0028] The second control circuit 2 includes a normally closed contact of an angle contactor KM2, a normally closed contact of an angle start button SB3, and a coil of a star contactor KM3 which are arranged in series in sequence;

[0029] The second control circuit 2 is connected in parallel with a third control circuit 3;

[0030] The third control circuit 3 includes a normally open contact of an angular contactor KM2, a normally closed contact of a star contactor KM3, and a coil of the angular contactor KM2, which are arranged in series in sequence. The normally open contact of the angular contactor KM2 is connected in parallel with a normally open contact of an angular start button SB3.

[0031] A fourth control circuit 4 is connected in parallel between the normally closed contact of the thermal relay FR of the first control circuit 1, the normally closed contact of the stop button SB1, the normally open contact of the star start button SB2, and the coil of the power contactor KM1;

[0032] The fourth control circuit 4 includes a normally closed contact of a power contactor KM1, a normally closed contact of a stop button SB1, and a first indicator light HL1 which are sequentially connected in series;

[0033] A fifth control circuit 5 is connected in parallel between the normally closed contact of the stop button SB1 of the fourth control circuit 4 and the first indicator light HL1;

[0034] The fifth control circuit 5 includes a normally closed contact of a star contactor KM3, a normally closed contact of an angle start button SB3, and a second indicator light HL2 which are sequentially connected in series;

[0035] A sixth control circuit 6 is connected in parallel between the normally closed contact of the angle start button SB3 of the fifth control circuit 5 and the second indicator light HL2;

[0036] The sixth control circuit 6 includes a normally closed contact of an angular contactor KM2 and a third indicator light HL3 which are sequentially connected in series;

[0037] The fourth control circuit 4 is connected in parallel with a seventh control circuit 7;

[0038] The seventh control circuit 7 includes a normally open contact of the power contactor KM1, a normally open contact of the star contactor KM3, a normally closed contact of the angle contactor KM2, and a fourth indicator light HL4 which are sequentially connected in series.

[0039] The specific operation process of this embodiment is as follows:

[0040] 1. Preparation stage;

[0041] Close the switch of circuit breaker QF;

[0042] Fourth control circuit 4: the normally closed contact of the power contactor KM1 is in a closed state. If the stop button SB1 is intact, the auxiliary normally closed contact of the stop button SB1 is in a closed state, and the first indicator light HL1 is on, indicating that the main power circuit is normal;

[0043] Fifth control circuit 5: When the normally closed contact of the power contactor KM1 and the normally closed contact of the star contactor KM3 are in good condition, and the angle start button SB3 is in good condition, the auxiliary normally closed contact of the angle start button SB3 is in a closed state, and the second indicator light HL2 is on, indicating that the star stop circuit is normal;

[0044] Sixth control circuit 6: When the normally closed contacts of the power contactor KM1 and the normally closed contacts of the star contactor KM3 are intact, and the angle contactor KM2 is intact, the normally closed contacts of the angle contactor KM2 are in a closed state, and the third indicator light HL3 is on, indicating that the star starting circuit is normal.

[0045] When the first indicator light HL1, the second indicator light HL2, and the third indicator light HL3 are all on, the vehicle is ready for starting:

[0046] 2. Starting process:

[0047] First control circuit 1: Press the star-shaped start button SB2, the coil of the power contactor KM1 is energized, and at the same time the normally open contact of the power contactor KM1 is closed, so that the coil of the power contactor KM1 is self-locking;

[0048] Second control circuit 2: At the same time, the coil of the star contactor KM3 is also energized, and the motor starts star operation;

[0049] Seventh control circuit 7: At this time, the normally open contact of the power contactor KM1 and the normally open contact of the star contactor KM3 are both in the closed state. If the angle contactor KM2 is intact, the normally closed contact of the angle contactor KM2 is in the normally closed state, and the fourth indicator HL4 lights up, indicating that the angle start circuit is normal and the angle operation can be started;

[0050] Second control circuit 2: Press the angle start button SB3 to disconnect the coil circuit of the star contactor KM3 and stop the star operation;

[0051] The third control circuit 3: the coil of the angular contactor KM2 is connected at the same time, and the angular contactor KM2 is energized and self-locked, and the motor runs in an angular manner;

[0052] Seventh control circuit 7: If the angle contactor KM2 is not intact and there is a problem of contact adhesion, the normally closed contact of the angle contactor KM2 is definitely not in the normally closed state, and the fourth indicator light HL4 is not on, indicating that the angle starting circuit is abnormal and the angle operation cannot be started.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A monitoring circuit to prevent star-delta reduced-voltage starting from becoming full-voltage starting, characterized in that: It includes a first control circuit, a second control circuit, a third control circuit, a fourth control circuit, a fifth control circuit, a sixth control circuit, and a seventh control circuit; The first control circuit includes a switch of a circuit breaker QF, a normally closed contact of a thermal relay FR, a normally closed contact of a stop button SB1, a normally open contact of a star-shaped start button SB2, and a coil of a power contactor KM1, which are sequentially arranged in series, and the normally open contact of the star-shaped start button SB2 is connected in parallel with the normally open contact of the power contactor KM1; The coil of the power contactor KM1 of the first control circuit is connected in parallel with the second control circuit; The second control circuit includes a normally closed contact of an angle contactor KM2, a normally closed contact of an angle start button SB3, and a coil of a star contactor KM3 which are sequentially arranged in series; The second control circuit is connected in parallel with a third control circuit; The third control circuit includes a normally open contact of an angular contactor KM2, a normally closed contact of a star contactor KM3, and a coil of the angular contactor KM2, which are sequentially arranged in series, and the normally open contact of the angular contactor KM2 is connected in parallel with the normally open contact of the angular start button SB3; The fourth control circuit is connected in parallel between the normally closed contact of the thermal relay FR of the first control circuit, the normally closed contact of the stop button SB1, the normally open contact of the star start button SB2, and the coil of the power contactor KM1; The fourth control circuit includes a normally closed contact of a power contactor KM1, a normally closed contact of a stop button SB1, and a first indicator light HL1 which are sequentially connected in series; The fifth control circuit is connected in parallel between the normally closed contact of the stop button SB1 of the fourth control circuit and the first indicator light HL1; The fifth control circuit includes a normally closed contact of a star contactor KM3, a normally closed contact of an angle start button SB3, and a second indicator light HL2 which are sequentially connected in series; The sixth control circuit is connected in parallel between the normally closed contact of the angle start button SB3 of the fifth control circuit and the second indicator light HL2; The sixth control circuit includes a normally closed contact of an angular contactor KM2 and a third indicator light HL3 which are arranged in series; The fourth control circuit is connected in parallel with the seventh control circuit; The seventh control circuit includes a normally open contact of a power contactor KM1, a normally open contact of a star contactor KM3, a normally closed contact of a corner contactor KM2, and a fourth indicator light HL4 which are sequentially connected in series.

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